Sorry. This should have been a private email. But now that it's in the wild, if_sk.c calls epoch_enter_preempt() at line 84 which causes panic early in boot.
-- Cheers, Cy Schubert <cy.schub...@cschubert.com> FreeBSD UNIX: <c...@freebsd.org> Web: http://www.FreeBSD.org The need of the many outweighs the greed of the few. In message <201811140933.wae9xxsl003...@slippy.cwsent.com>, Cy Schubert writes: > In message <201811132258.wadmwctl063...@repo.freebsd.org>, Gleb > Smirnoff writes > : > > Author: glebius > > Date: Tue Nov 13 22:58:38 2018 > > New Revision: 340413 > > URL: https://svnweb.freebsd.org/changeset/base/340413 > > > > Log: > > For compatibility KPI functions like if_addr_rlock() that used to have > > mutexes but now are converted to epoch(9) use thread-private epoch_tracke > r. > > Embedding tracker into ifnet(9) or ifnet derived structures creates a non > > reentrable function, that will fail miserably if called simultaneously fr > om > > two different contexts. > > A thread private tracker will provide a single tracker that would allow t > o > > call these functions safely. It doesn't allow nested call, but this is no > t > > expected from compatibility KPIs. > > > > Reviewed by: markj > > > > Modified: > > head/sys/kern/kern_thread.c > > head/sys/kern/subr_epoch.c > > head/sys/net/if.c > > head/sys/net/if_var.h > > head/sys/sys/epoch.h > > head/sys/sys/proc.h > > > > Modified: head/sys/kern/kern_thread.c > > =========================================================================== > == > > = > > --- head/sys/kern/kern_thread.c Tue Nov 13 22:41:20 2018 (r34041 > > 2) > > +++ head/sys/kern/kern_thread.c Tue Nov 13 22:58:38 2018 (r34041 > > 3) > > @@ -272,6 +272,7 @@ thread_init(void *mem, int size, int flags) > > td->td_rlqe = NULL; > > EVENTHANDLER_DIRECT_INVOKE(thread_init, td); > > umtx_thread_init(td); > > + epoch_thread_init(td); > > td->td_kstack = 0; > > td->td_sel = NULL; > > return (0); > > @@ -291,6 +292,7 @@ thread_fini(void *mem, int size) > > turnstile_free(td->td_turnstile); > > sleepq_free(td->td_sleepqueue); > > umtx_thread_fini(td); > > + epoch_thread_fini(td); > > seltdfini(td); > > } > > > > > > Modified: head/sys/kern/subr_epoch.c > > =========================================================================== > == > > = > > --- head/sys/kern/subr_epoch.c Tue Nov 13 22:41:20 2018 (r34041 > > 2) > > +++ head/sys/kern/subr_epoch.c Tue Nov 13 22:58:38 2018 (r34041 > > 3) > > @@ -667,3 +667,17 @@ in_epoch(epoch_t epoch) > > { > > return (in_epoch_verbose(epoch, 0)); > > } > > + > > +void > > +epoch_thread_init(struct thread *td) > > +{ > > + > > + td->td_et = malloc(sizeof(struct epoch_tracker), M_EPOCH, M_WAITOK); > > +} > > + > > +void > > +epoch_thread_fini(struct thread *td) > > +{ > > + > > + free(td->td_et, M_EPOCH); > > +} > > > > Modified: head/sys/net/if.c > > =========================================================================== > == > > = > > --- head/sys/net/if.c Tue Nov 13 22:41:20 2018 (r340412) > > +++ head/sys/net/if.c Tue Nov 13 22:58:38 2018 (r340413) > > @@ -1767,35 +1767,29 @@ if_data_copy(struct ifnet *ifp, struct if_data *ifd > ) > > void > > if_addr_rlock(struct ifnet *ifp) > > { > > - MPASS(*(uint64_t *)&ifp->if_addr_et == 0); > > - epoch_enter_preempt(net_epoch_preempt, &ifp->if_addr_et); > > + > > + epoch_enter_preempt(net_epoch_preempt, curthread->td_et); > > } > > > > void > > if_addr_runlock(struct ifnet *ifp) > > { > > - epoch_exit_preempt(net_epoch_preempt, &ifp->if_addr_et); > > -#ifdef INVARIANTS > > - bzero(&ifp->if_addr_et, sizeof(struct epoch_tracker)); > > -#endif > > + > > + epoch_exit_preempt(net_epoch_preempt, curthread->td_et); > > } > > > > void > > if_maddr_rlock(if_t ifp) > > { > > > > - MPASS(*(uint64_t *)&ifp->if_maddr_et == 0); > > - epoch_enter_preempt(net_epoch_preempt, &ifp->if_maddr_et); > > + epoch_enter_preempt(net_epoch_preempt, curthread->td_et); > > > Hi Gleb, > > I was wrong. It's happening here, called from line 084 in if_sk.c. > > ~cy > > > } > > > > void > > if_maddr_runlock(if_t ifp) > > { > > > > - epoch_exit_preempt(net_epoch_preempt, &ifp->if_maddr_et); > > -#ifdef INVARIANTS > > - bzero(&ifp->if_maddr_et, sizeof(struct epoch_tracker)); > > -#endif > > + epoch_exit_preempt(net_epoch_preempt, curthread->td_et); > > } > > > > /* > > > > Modified: head/sys/net/if_var.h > > =========================================================================== > == > > = > > --- head/sys/net/if_var.h Tue Nov 13 22:41:20 2018 (r340412) > > +++ head/sys/net/if_var.h Tue Nov 13 22:58:38 2018 (r340413) > > @@ -381,8 +381,6 @@ struct ifnet { > > */ > > struct netdump_methods *if_netdump_methods; > > struct epoch_context if_epoch_ctx; > > - struct epoch_tracker if_addr_et; > > - struct epoch_tracker if_maddr_et; > > > > /* > > * Spare fields to be added before branching a stable branch, so > > > > Modified: head/sys/sys/epoch.h > > =========================================================================== > == > > = > > --- head/sys/sys/epoch.h Tue Nov 13 22:41:20 2018 (r340412) > > +++ head/sys/sys/epoch.h Tue Nov 13 22:58:38 2018 (r340413) > > @@ -82,5 +82,8 @@ void epoch_exit_preempt(epoch_t epoch, epoch_tracker_t > > void epoch_enter(epoch_t epoch); > > void epoch_exit(epoch_t epoch); > > > > +void epoch_thread_init(struct thread *); > > +void epoch_thread_fini(struct thread *); > > + > > #endif /* _KERNEL */ > > #endif /* _SYS_EPOCH_H_ */ > > > > Modified: head/sys/sys/proc.h > > =========================================================================== > == > > = > > --- head/sys/sys/proc.h Tue Nov 13 22:41:20 2018 (r340412) > > +++ head/sys/sys/proc.h Tue Nov 13 22:58:38 2018 (r340413) > > @@ -193,6 +193,7 @@ struct trapframe; > > struct turnstile; > > struct vm_map; > > struct vm_map_entry; > > +struct epoch_tracker; > > > > /* > > * XXX: Does this belong in resource.h or resourcevar.h instead? > > @@ -360,6 +361,7 @@ struct thread { > > int td_lastcpu; /* (t) Last cpu we were on. */ > > int td_oncpu; /* (t) Which cpu we are on. */ > > void *td_lkpi_task; /* LinuxKPI task struct pointer */ > > + struct epoch_tracker *td_et; /* (k) compat KPI spare tracker */ > > int td_pmcpend; > > }; > > > > > > > -- > Cheers, > Cy Schubert <cy.schub...@cschubert.com> > FreeBSD UNIX: <c...@freebsd.org> Web: http://www.FreeBSD.org > > The need of the many outweighs the greed of the few. > > > _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
